gio:menu-item-set-detailed-action (item action)

item -- a g:menu-item object
action -- a detailed action string

Sets the "action" attribute and possibly the "target" attribute of the menu item. The format of action is the same format parsed by the g:action-parse-detailed-name function.

See the g:menu-item-set-action-and-target-value function for a more flexible, but slightly less convenient, alternative. See also the g:menu-item-set-action-and-target-value function for a description of the semantics of the "action" and "target" attributes.